1. Field of the Invention
The present invention relates to a system and method that restrain a vehicle occupant with a seat belt.
2. Description of the Related Art
Occupant restraint systems in the known art include the system disclosed in Japanese Laid-Open Patent Publication No. H 09-132113. This occupant restraint system judges the condition manifesting between the vehicle and an object present ahead of the vehicle based upon the results of a detection of the object by an object detection sensor and adjusts the tension of a seat belt with an electric motor in conformance to the condition manifesting between the vehicle and the object. In addition, there is a mechanical lock device in the related art that prevents the seat belt from being drawn out if the vehicle undergoes a deceleration to an extent equal to or greater than a predetermined value through emergency braking or the like. Another mechanical lock device in the related art prevents a seat belt from feeding out if it is pulled abruptly.
In addition, there are occupant restraint systems in the related art that detect that the vehicle is currently traveling in a turn along a winding road by utilizing a steering angle sensor or the like when there is another vehicle approaching from the opposite direction on the other side of the winding road as the vehicle travels with its wheels turned on the outer side of the winding road, and adjust the tension of the seat belt.
However, the occupant restraint systems that detects an object present ahead of the vehicle with an object detection sensor described above is bound to be costly.
In the mechanical seat belt lock devices described above, factors such as play in the lock mechanism, slack in the seat belt as it is being taken up, stretching of the seat belt itself and slack in the seat belt as it is fastened are present. For this reason, the upper body of the occupant moves forward for a while even after the seat belt is locked, and thus, it is difficult to restrain the upper body of the occupant with a high degree of reliability at an early stage. This gives rise to a problem in that it is difficult to give the occupant a restricting feeling effectively.
It is desirable that the present invention provides an occupant restraint system that restrains an occupant of a vehicle in an effective manner with a seat belt.
An occupant restraint system comprises a seat belt tension application device that adjusts tension applied to a seat belt to restrain an occupant with the seat belt, a longitudinal acceleration detector that detects a longitudinal acceleration occurring in a vehicle along a longitudinal direction, a lateral acceleration detector that detects a lateral acceleration occurring in the vehicle along a lateral direction, and a control device that controls the tension applied by the seat belt tension application device based upon a longitudinal acceleration detection value detected by the longitudinal acceleration detector and a lateral acceleration detection value detected by the lateral acceleration detector. A two-dimensional map, with a deceleration (negative acceleration) occurring in the vehicle along the longitudinal direction set on a + side of one of two axes orthogonally intersecting each other in a two-dimensional coordinate system, an acceleration of the vehicle occurring along the longitudinal direction set on a xe2x88x92 side of the one axis, an acceleration of the vehicle to a right set on a + side of the other axis in the two-dimensional coordinate system and an acceleration of the vehicle to a left set on a xe2x88x92 side of the other axis, is provided, and an operation decision-making threshold line, which forms one of a semi-elliptic shape and a polygonal shape, intersects the other axis on the + side at A, intersects the other axis on the xe2x88x92 side at xe2x88x92A and intersects the one axis on the + side at +B satisfying B less than A, is set in a first quadrant and a second quadrant of the map. The control device engages the seat belt tension application device to apply the tension to the seat belt if a point on the map determined in conformance to the longitudinal acceleration detection value and the lateral acceleration detection value obtained as the vehicle decelerates is outside a range enclosed by the operation decision-making threshold line and the other axis.
An occupant restraint system comprises a seat belt tension application device that adjusts tension applied to a seat belt to restrain an occupant with the seat belt, a longitudinal acceleration detector that detects a longitudinal acceleration occurring in a vehicle along a longitudinal direction, a lateral acceleration detector that detects a lateral acceleration occurring in the vehicle along a lateral direction, and a control device that controls the tension applied by the seat belt tension application device based upon a longitudinal acceleration detection value detected by the longitudinal acceleration detector and a lateral acceleration detection value detected by the lateral acceleration detector. An XY two-dimensional map, with a deceleration (negative acceleration) of the vehicle occurring along the longitudinal direction set on a +Y axis, an acceleration of the vehicle occurring along the longitudinal direction set on a xe2x88x92Y axis, an acceleration of the vehicle to a right set on a +X axis and an acceleration of the vehicle to a left set on a xe2x88x92X axis, is provided, and a first operation decision-making threshold line, which forms one of a semi-elliptic shape and a polygonal shape, intersects the +X axis at A, intersects the xe2x88x92X axis at xe2x88x92A and intersects the +Y axis at +B satisfying B less than A, is set in a first quadrant and a second quadrant of the map. The control device engages the seat belt tension application device to apply the tension to the seat belt if a point on the map determined in conformance to the longitudinal acceleration detection value and the lateral acceleration detection value obtained as the vehicle decelerates is outside a range enclosed by the first operation decision-making threshold line and the X axis.
An occupant restraint system comprises a seat belt tension application device that adjusts tension applied to a seat belt to restrain an occupant with the seat belt, a longitudinal acceleration detector that detects a longitudinal acceleration occurring in a vehicle along a longitudinal direction, a lateral acceleration detector that detects a lateral acceleration occurring in the vehicle along a lateral direction, and a control device that controls the tension applied by the seat belt tension application device based upon a longitudinal acceleration detection value detected by the longitudinal acceleration detector and a lateral acceleration detection value detected by the lateral acceleration detector. An XY two-dimensional map, with a deceleration (negative acceleration) of the vehicle occurring along the longitudinal direction set on a +Y axis, an acceleration of the vehicle occurring along the longitudinal direction set on a xe2x88x92Y axis, an acceleration of the vehicle to a right set on a +X axis and an acceleration of the vehicle to a left set on a xe2x88x92X axis, is provided, and an operation decision-making threshold line, which forms a substantial semi-elliptic shape achieved by connecting a plurality of quadratic curves at a plurality of inflection points intersects the +X axis at A, intersects the xe2x88x92X axis at xe2x88x92A and intersects the +Y axis at +B satisfying B less than A, is set in a first quadrant and a second quadrant of the map. The control device engages the seat belt tension application device to apply the tension to the seat belt if a point on the map determined in conformance to the longitudinal acceleration detection value and the lateral acceleration detection value obtained as the vehicle decelerates is outside a range enclosed by the semi-elliptic operation decision-making threshold line and the X axis.
An occupant restraint system comprises a seat belt tension application device that adjusts tension applied to a seat belt to restrain an occupant with the seat belt, a longitudinal acceleration detector that detects a longitudinal acceleration occurring in a vehicle along a longitudinal direction, a lateral acceleration detector that detects a lateral acceleration occurring in the vehicle along a lateral direction, and a control device that controls the tension applied by the seat belt tension application device based upon a longitudinal acceleration detection value detected by the longitudinal acceleration detector and a lateral acceleration detection value detected by the lateral acceleration detector. An XY two-dimensional map, with a deceleration (negative acceleration) of the vehicle occurring along the longitudinal direction set on a +Y axis, an acceleration of the vehicle occurring along the longitudinal direction set on a xe2x88x92Y axis, an acceleration of the vehicle to a right set on a +X axis and an acceleration of the vehicle to a left set on a xe2x88x92X axis, is provided, and an operation decision-making threshold line, which forms a polygonal shape achieved by connecting a plurality of sides at, at least, one inflection point intersects the +X axis at A, intersects the xe2x88x92X axis at xe2x88x92A and intersects the +Y axis at +B satisfying B less than A, is set in a first quadrant and a second quadrant of the map. The control device engages the seat belt tension application device to apply the tension to the seat belt if a point on the map determined in conformance to the longitudinal acceleration detection value and the lateral acceleration detection value obtained as the vehicle decelerates is outside a range enclosed by the polygonal operation decision-making threshold line and the X axis.
An occupant restraint system comprises a seat belt tension application means for adjusting tension applied to a seat belt to restrain an occupant with the seat belt, a longitudinal acceleration detection means for detecting a longitudinal acceleration occurring in a vehicle along a longitudinal direction, a lateral acceleration detection means for detecting a lateral acceleration occurring in the vehicle along a lateral direction, and a control means for controlling the tension applied by the seat belt tension application means based upon a longitudinal acceleration detection value detected by the longitudinal acceleration detection means and a lateral acceleration detection value detected by the lateral acceleration detection means. A two-dimensional map, with a deceleration (negative acceleration) occurring in the vehicle along the longitudinal direction set on a + side of one of two axes orthogonally intersecting each other in a two-dimensional coordinate system, an acceleration of the vehicle occurring along the longitudinal direction set on a xe2x88x92 side of the one axis, an acceleration of the vehicle to a right set on a + side of the other axis in the two-dimensional coordinate system and an acceleration of the vehicle to a left set on a xe2x88x92 side of the other axis, is provided, and an operation decision-making threshold line connecting an intersecting point +A at which the other axis is intersected on the + side, an intersecting point xe2x88x92A at which the other axis is intersected on the xe2x88x92 side and an intersecting point +B satisfying B less than A at which the one axis is intersected on the + side is set in a first quadrant and a second quadrant of the map. The control means engages the seat belt tension application means to apply the tension to the seat belt if a point on the map determined in conformance to the longitudinal acceleration detection value and the lateral acceleration detection value obtained as the vehicle decelerates is outside a range enclosed by the operation decision-making threshold line and the other axis.
An occupant restraint method achieved by using a two-dimensional map, with a deceleration (negative acceleration) of a vehicle occurring along a longitudinal direction set on a + side of one of two axes orthogonally intersecting each other in a two-dimensional coordinate system, an acceleration of the vehicle occurring along the longitudinal direction set on a xe2x88x92 side of the one axis, an acceleration of the vehicle to a right set on a + side of the other axis in the two-dimensional coordinate system and an acceleration of the vehicle to a left set on a xe2x88x92 side of the other axis, in which a semi-elliptic or polygonal decision-making threshold line intersecting the other axis on the + side at A, intersecting the other axis on the xe2x88x92 side at xe2x88x92A and intersecting the one axis on the + side at +B satisfying B less than A is set, comprises detecting an acceleration of the vehicle occurring along the longitudinal direction; detecting an acceleration of the vehicle occurring along the lateral direction; and applying tension to a seat belt so as to restrain an occupant when a point on the map determined in conformance to a longitudinal acceleration detection value and a lateral acceleration detection value obtained as the vehicle decelerates is outside a range enclosed by the operation decision-making threshold line and the other axis.